Allegations that the Roman Catholic Archdiocese of Boston systematically concealed accusations that clergy sexually abused hundreds of children sparked a nationwide church scandal last year. An official investigation concludes that the extent of the crisis is "staggering".

Massachusetts Attorney General Tom Reilly found that the Boston Archdiocese's own records reveal that 789 alleged victims in dozens of towns accused clergy of sexual abuse. But he says the number of victims, spanning a period from 1940 to today, probably exceeds 1,000. "What we have documented in the course of this investigation borders on the unbelievable. The duration of it, six decades of the sexual abuse of children by members of the catholic clergy. The magnitude of it is simply staggering," he said.

News of the scandal roiled Roman Catholic communities throughout the United States, leading to the resignation of Cardinal Bernard Law of Boston. Many parishioners demanded changes in the way the church is run when they learned that church officials protected accused priests and failed to forward alleged abuse cases to law enforcement authorities.

Since then, some states, including Massachusetts and New York, have passed legislation requiring clergy to report child abuse to the state.

The Massachusetts attorney general's findings follow a U.S. grand jury investigation into whether leaders of the Boston Archdiocese should face criminal charges for overlooking allegations of abuse and shuffling accused priests to different parishes. He released his conclusions in a 91-page report.

Attorney General Reilly said former Archbishop Cardinal Bernard Law bears ultimate responsibility for what he calls the "tragic treatment of children." He also holds senior church leaders accountable for not taking steps to end systematic abuse. "The Catholic faith and the Catholic religion values and teaches to protect the most vulnerable, particularly our children. Now this is not about the Catholic faith and the Catholic religion," he said. "This is a massive, inexcusable failure of leadership in the Archdiocese of Boston."

But the Massachusetts attorney general will not file criminal charges against Bernard Law and other high level church officials because child protection laws were weak at the time of the alleged wrong-doings.

Attorney General Reilly said he hopes his report will draw a clear line between the past and a more hopeful future. He also provides suggestions to prevent future abuse. Several alleged victims have protested the decision not to indict the Boston church officials. The Boston Archdiocese is facing hundreds of financially crippling civil suits.